FIG. 1 is a network configuration diagram of a mobile communication system using a wireless LAN.
Referring to FIG. 1, a wireless access network 100 of the LTE (Long-Term Evolution) mobile communication system as an example of a mobile communication system is shown. The wireless access network 100 includes an eNB (eNodeB; evolved Node B) 110, an MME (Mobility Management Entity) 120, an SGW (Serving-Gateway) 130, and a PGW (PDN-Gateway; Packet Data Network Gateway) 140. UE (User Equipment) is connected to an external network through the eNB 110, the SGW 130, and the PGW 140.
The eNB 110 corresponds to an existing node B of the UMTS system. The eNB 110 is connected to the UE 135 through a wireless channel. The eNB 110 performs a more complicated role than the existing node B does.
According to the LTE system, all user traffics including a real-time service such as VoIP (Voice over Internet Protocol) are serviced through a shared channel. Therefore, the LTE system requires an apparatus for collecting circumstantial information about the UEs 135 and thereby performing a scheduling. The eNB 110 takes charge of this function.
The SGW 130 is an apparatus for offering data bearer, and creates or removes data bearer under the control of the MME 120. The MME 120 is an apparatus for taking charge of various control functions, and one MME 120 may be connected to two or more eNBs 110.
The UE 135 can access the PGW 140 of the LTE system through a wireless local area network access point (WLAN AP) 150 and then transmit or receive data. However, according to conventional technology, in case the UE 135 accesses the PGW 140 through the WLAN AP 150, it should use ePDG (enhanced Packet Data Gateway) 160 which is an additional node for security, QoS (Quality of Service) mapping, or the like.
The unit to which QoS can be applied in a wireless communication system such as LTE is a bearer. One bearer is used for transmitting IP flows having the same QoS requirements. A parameter associated with QoS may be specified in a bearer, including QCI (QoS Class Identifier) and ARP (Allocation Retention Priority). One IP address corresponds to one PDN connection. A plurality of bearers may belong to one PDN connection.
As shown in FIG. 1, it is possible for the UE 135 to simultaneously use an LTE access network and a WLAN even in a convention LTE system. However, since a service is provided in the form of sharing the PGW 140 only between the WLAN and the LTE network in the current network structure, the UE 135 should use different IP addresses allocated for each of the WLAN and the LTE. This may cause a waste of an IP address. Further, considering reality that one application normally uses one IP address, it is difficult to provide a service simultaneously using the WLAN and the LTE with regard to one application. Additionally, since the LTE and the WLAN operate separately from each other, it is difficult to efficiently manage resources. Also, for utilizing the WLAN, an operator should invest in an additional network component such as ePDG 160.